Refrigerating apparatus



H. B. HULL Dec. 15, 1931.

Filed Sept. 29. 1927 2 Sheets-Sheet 1 H II l 21 condenser Dec. 15, 1931. f H. B. Quu. 1,836,072

REFRIGERATING APPARATUS Filed Se pt. 29. 1927 2 Sheets$heet 2 2 gmiw 67 0 M' WW 0 4 Patented Dec. 15, 1931 UNITED STATES PATENT OFFICE HARRY B. HULL, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO FRIG- IDAIRE CORPORATION, A CORPORATION OF DELAWARE marenmrnve APPARATUS- Application filed September 29, 1927. Serial No. 222,900.

This invention relates to refrigerating apparatus of the compressor-condenser-expander type and particularly to that class of such which the refrigerant is evaporated is maintained substantially uniform.

Another object is to provide improved means for adjusting and regulating the pressure under which the refrigerant is evaporated. More specifically it is an object of the invention to provide an improved expansion valve which is readily adjustable and which will operate to provide a substantially uniform refrigerant pressure or which can be readily adjusted to give any desired change of pressure during operation.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown. I

In the drawings Fig. 1 is a dia ammatic illustration of my invention app ied to a conventional refrigerating system;

Fig. 2 is a section of an expansion valve cogstructed in accordance with my invention; an v Fig. 3 is a vertical section of a refrigerator cabinet showing in elevation the refrigerating ipparatus diagrammatically illustrated in ig. 1. j

Referring to Figs. 1 and 2 it is usual to provide a refrigerating system having a compressor 10, a'condenser 11, a pressure-responsive expansion valve 12 and an evaporator 13. The compressormay be driven by a motor 14 under the control of a switch 15 actuated by a thermostat 16 responsive to the temperature of the evaporator. In such systems the expansion valve controls the flow of liquid refrigerant into the evaporator in response to the pressure existing within the evaporator. This is accomplished by means such as shown in Fig. 2 wherein 20 is a conduit supplying liquid refrigerant at high pressure from the condenser to the expansion valve, and'21 is a conduit supplying the liquid refrigerant at low pressure to the evaporator.

These conduits are connectedto a casing 22 in which is a chamber 23 in which, it will be evident, the pressure existing in the evaporator is maintained. Liquid refri erant enters this chamber through the ori ce 24 under the control of a needle valve 25 which is carried on a yoke 26 attached to a flexible dia-v phragm 27 forming one wall of the chamber 23. The other side of the diaphragm is ex posed to substantially atmospheric pressure. Attached to the diaphragm and to the yoke is a post 30 which forms a rigid structure with the yoke and needle valve 25. This post is urged to the left as shown in Fig. 2 by a spring 31 compressed between a rigid abutment 28 and adjusting nuts 32 threaded on the post. Thus it will be seen that the spring urges the diaphragm and yoke to the leftand tends to close the valve.

From the foregoing it will be apparent that whenever the pressure within the chamber 23 is reduced sufliciently below that of the atmosphere, the atmospheric pressure on the diaphragm 27 will open the valve against the force of the spring, and that the amount of such opening will be dependent upon the actual value of the pressure existing in the chamber 23 and hence in the evaporator. Thus whenever the pressure within the evaporator is reduced to a value below that corresponding to the setting of a corresponding to the spring setting the valve will be closed. Thus theoretically the valve maintains a constant pressure within this evaporator.

However, it has been found from actual experience that the pressure within the evap-v orator gradually decreases during continued operation of the compressor. This not only changes the temperature at which the evapthe valve casing.

ordinarily the coldest part of the refrigeratorator operates but also changes the pressure ing system. Consequently during operation of the compressor the valve becomes coated with frost. If the diaphragm and spring were left open to the atmosphere these would become coated with frost and the valve could not operate. Consequently it has been the practice to enclose the atmospheric side of the diaphragm and the spring and adjusting mechanism by casing 33 having a chamber 34 which is sealed from the atmosphere by a closure plug or cap 35. When the expansion valve is warm, for instance When the apparatus begins to operate, the air confined within chamber 34 exerts definite pressure on the diaphragm corresponding to the temperature of the valve. However, as the apparatus continues to refrigerate, the expansion valve casing and its associated parts becom e cold. Consequently the air confined within the chamber 34 now exerts a smaller pressure on the diaphragm corresponding to this reduced temperature. This reduction in pressure during operation naturally tends to close the valve and produces the drop of pressure inthe evaporatorreferred to. In accordance with my invention I ellm nate this change of pressure on the atmospheric side of the diaphragm and'keep a constant pressure in the chamber 34 irrespective of temperature changes of the valve.

Referring to Fig. 3 the compressor, condenser and motor are disposed outside the refrigerating compartment 40 of the cabinet 41, all as more fully disclosed inmy application Serial No. 183,480 filed April 12, 1927. And as is well known these parts of the apparatus gradually become warmer during operation. This is necessarily true, since the motor and compressor are inherently constructed so that they heat up during operation, and since the condenser is for the very'purpose of dissipating'into the atmosphere the heat absorbed from the chamber 40 by the evaporator. Because these parts of the apparatus become warmer during operation I designate them, for the urpose of this invention, as heating means. n accordance withthe invention Iplace in thermal association with any of said heating means, preferably the condenser, a. closed chamber 5 containing air at atmospheric pressure. This; chamber is connected by means of a slendr tube 51 with a duct 52 in the casing 133, "leading to the chamber 34 associated with the diaphragm of the expansion valve.

Consequently as the apparatus operates and as the temperature of the expansion valve is gradually reduced the temperature of the bulb 50 is graduallyincreased; therefore by selecting the point at which the chamber 50 is placed, any desired degree of compensation of the expansion valve through any desired range of operation may be obtained. Thus the expansion valve may be set to maintain a uniform pressure. Or if it is found gesirable, the pressure may be permitted to rop continues by under-compensating the valve, for instance by making the volume of the chamber 50 smaller than the volume of the chamber 34. On the other hand the pressure in the evaporator may be permitted to increase slightly during operation of the compressor by over-compensating expansion valve by making the volume of the chamber 50 larger than the volume of the chamber 34. The same results may likewise be accomplished by varying the temperature changes of the bulb 50 by choosing the place where it is located.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might beado ted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant through the evaporator including heating dissipating means arranged to increase in temperature when refrigerant is circulated, means responsive to the pressure of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, and means thermally associated with the heating dissipating means for influencing the action of the controlling means.

2. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant through the evaporator including a condenser, means responsive to the pressure of the refrigerant in the evaporator for controlling the flow of refri erant to the evaporator, and means thermal y associated with the condenser for influencing the action of the controlling means.

3. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant through the evaporator in-j dissipating means arranged for controlling the flow of refrigerant to the evaporator, aclosed gas chamber associated slightly in the evaporator as operation with the diaphragm, a closed gas chamber thermally associated with the heating dissipating means and a pressure-equalizing connection between said chambers.

4. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant through the evaporator including heating dissipating means arranged to increase in temperature when refrigerant is circulated, a valve-for controlling'the flow of refrigerant to the evaporator, a diaphragm responsive to the pressure in the evaporator for moving the valve in one direction, a spring for moving the valve in the other direction, a closed chamber surrounding the spring, a closed gas chamber thermally associated with the heating dissipating means, and a pressure-equalizing connection between said chambers.

5. Refrigerating apparatus comprising in combination an evaporator, means for circulating refrigerant through the evaporator including heating dissipating means arranged to increase in temperature when refrigerant is circulated, a valve for controlling the flow of refrigerant 'to the evaporator, a diaphragm responsive to the pressure in the evaporator for moving the valve in one direction, a spring for moving the valve in the other direction,

means for adjusting the spring, a chamber enclosing the spring and adjusting means, a removable closure for said chamber permitting access to said adjusting means and adapted to seal the chamber, a closed gas chamber thermally associated with the heating dissipating means, and a pressure-equalizing connection between said chambers.

In testimony whereof I hereto aflix my signature.

Y HARRY B, HULL. 

